Anti-bacterial light delivery system and method for disinfecting a surface

ABSTRACT

A light delivery system and method are provided to promote a photochemical reaction for disinfecting a surface. The system includes a light source and a light diffusing element operatively coupled to the light source and further embedded within a surface to be disinfected. The light diffusing element outputs light to the surface to promote a photochemical reaction to disinfect the surface. A low scatter light transmission medium may further be coupled between the light source and the light diffusing element to transmit light from the light source remotely to the light diffusing element.

This application claims the benefit of priority under 35 U.S.C. §119 ofU.S. Provisional Application Ser. No. 61/908915 filed on Nov. 26, 2013the contents of which are relied upon and incorporated herein byreference in their entirety as if fully set forth below.

BACKGROUND

This disclosure pertains to a light delivery system to promotephotochemical reaction for disinfecting a surface to provide a sterileenvironment.

Anti-bacterial applications or disinfectants are commonly applied tosurfaces, such as surgery tables or other surfaces in clean rooms andother environments to provide sterile surfaces. Known anti-bacterialtreatments typically involve applying an anti-bacterial lotion or liquidto the surface to kill bacteria to thereby decontaminate and clean thesurface. It is desirable to provide a means for disinfecting a surfacethat does not require the time and expense of applying an anti-bacteriallotion or liquid to the surface.

SUMMARY

In accordance with one embodiment, a light delivery system to promote aphotochemical reaction for disinfecting a surface is provided. Thesystem includes a light source and a light diffusing element operativelycoupled to the light source and further embedded within a surface to bedisinfected. The light diffusing element outputs light to the surface topromote a photochemical reaction to disinfect the surface.

In accordance with another embodiment, a method of disinfecting asurface by promoting a photochemical reaction is provided. The methodincludes the steps of coupling a light diffusing element to a surface tobe disinfected, supplying light having a wavelength to promote aphotochemical reaction to the light diffusing element, and applying thelight output from the light diffusing element to the surface to promotea photochemical reaction to disinfect the surface.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from that description or recognized by practicing theembodiments as described herein, including the detailed descriptionwhich follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary, and areintended to provide an overview or framework to understanding the natureand character of the claims. The accompanying drawings are included toprovide a further understanding, and are incorporated in and constitutea part of this specification. The drawings illustrate one or moreembodiments, and together with the description serve to explainprinciples and operation of the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic cross-sectional view of one embodiment of alight diffusing fiber useful as a light diffusing element in a lightdelivery system;

FIG. 2 is a top schematic diagram illustrating a light delivery systemfor promoting photochemical reaction for disinfecting a surface with theuse of the light diffusing element, according to one embodiment;

FIG. 3 is a perspective view illustrating the light diffusing elementembedded in a channel in the surface of a table, according to oneembodiment;

FIG. 4 is a cross-sectional view taken through line IV-IV of FIG. 3further illustrating the table;

FIG. 5 is an exploded view of the table and the embedded light diffusingelement of FIG. 3;

FIG. 6 is a perspective view of a light delivery system employing thelight diffusing element embedded in a table around a perimeter of thetable surface, according to a second embodiment;

FIG. 7 is a cross-sectional view taken through line VI-VI of FIG. 5further illustrating the table; and

FIG. 8 is an exploded view of the table and work surface furtherillustrating the arrangement of the light diffusing element embeddedaround the perimeter of the table and work surface shown in FIG. 5.

DETAILED DESCRIPTION

Reference will now be made in detail to the present preferredembodiments, examples of which are illustrated in the accompanyingdrawings. Whenever possible, the same reference numerals will be usedthroughout the drawings to refer to the same or like parts.

The following detailed description represents embodiments that areintended to provide an overview or framework for understanding thenature and character of the claims. The accompanied drawings areincluded to provide a further understanding of the claims and constitutea part of the specification. The drawings illustrate variousembodiments, and together with the descriptions serve to explain theprinciples and operations of these embodiments as claimed.

Referring to FIGS. 1-4, a light delivery system 10 is illustrated forpromoting a photochemical reaction for disinfecting a surface 12 of anobject, such as the work surface of a table 15. The light deliverysystem 10 employs an active light and an optional photocatalyst topromote a photochemical reaction in the volume on the surface 12 of thetable 15 to disinfect the table surface. The light applied to illuminatethe surface 12 may include light having a wavelength that serves to killgerms or inhibit the growth of microorganisms such as bacteria. Thelight may be used alone or may be used in combination with aphotocatalyst such as rutile TiO₂. The light wavelength may be in therange of 200 nm to 2000 nm, according to one embodiment. According to aspecific embodiment, an ultraviolet (UV) light having a wavelength inthe range of 200 to 400 nm may be used. The light may include acombination of wavelengths and may include a red laser light that isknown to help increase sterility. Further, combinations of infrared (IR)light can also be used as an additional heat source for accelerating thephotochemical processes.

The light delivery system 10 includes at least one electrically poweredlight source 16 for generating and supplying an active light with selectwavelength(s) to promote the photochemical reaction. The light source 16may be a collimated or Lambertian light source. The light source 16 mayinclude one or more lasers, light emitting diodes (LEDs), incandescentbulbs, ultraviolet lamps or a combination of light sources. The lightsource(s) 16 may generate light having a unique color or may combinevarious colors, such as red, green and blue light sources to generatecustom colors. In one embodiment, one or more ultraviolet light sourcesare employed.

The light delivery system 10 also includes at least one light diffusingelement 30 operatively coupled to the light source 16 to receive thelight supplied by the light source 16 and disperses the light. The lightdiffusing element 30 is embedded within surface 12 of the table 15 to bedisinfected. The light diffusing element 30 is a high scatter lighttransmission fiber that receives the light generated by light source 16and scatters and outputs the light to the surface 12 to promote aphotochemical reaction to disinfect the surface 12. The high scatterlight transmission achieved with the light diffusing element 30 has alight attenuation of 0.5 dB/meter or greater. The light diffusingelement 30 may include one or more light diffusing fibers, according toone embodiment, disposed within a channel 24 or within a plurality ofchannels 24 formed in the table 15 such as are shown in FIGS. 3 and 4.According to another embodiment, the light diffusing element 30 mayinclude one or more light diffusing rods.

The surface 12 may be the top work surface of a table 15 such as asurgical or operating table, a laboratory table, a countertop table inthe home or office, or any other table surface. The surface 12 may beassociated with other objects such as toilet seats, handles, and otherobjects, according to other embodiments. In one exemplary embodiment,the surface 12 may be the work surface of a table 15 used in a cleanroom 14 (e.g., operating room) for hospitals. The table 15 includes apanel 22 having a top surface, a bottom surface, an edge around theperiphery and channels 24 shown formed in the top surface for receivingthe light diffusing element 30. A light transmissive cover 26 may bedisposed on top of panel 22 to allow light generated by the lightdiffusing element 30 to illuminate the top surface 12. The cover 26 maybe translucent such that the light is transmitted through the cover 26and diffused. A reflective surface 28 may be provided on the inner sidewalls and bottom wall of channels 24 to reflect the light upwardstowards the top surface 12. In one embodiment, the panel 22 may includea metal material and the cover 26 may include a glass overlay and themetal panel 22 may include light reflective proportions to eliminate theneed for an additional reflective surface. The channel(s) 24 and lightdiffusing element 30 may be arranged in various shapes and sizes toproperly illuminate select areas or the entire surface to bedisinfected. While the table 15 shown is rectangular, it should beappreciated that other shapes and sizes may be used.

The light delivery system 10 may further include a low scatter lighttransmission medium 18 coupled between the light source 16 and the lightdiffusing element 30. According to one embodiment, the low scatter lighttransmission medium 18 may include an optical fiber designed to transmitlight with low signal loss. The low scatter light transmission achievedwith the transmission medium 18 has a light attenuation of less than 0.5dB/meter. The low scatter light transmission medium 18 is shown in oneembodiment coupled to the light diffusing element 30 by way of anoptical coupler 20. It should be appreciated that the low scatter lighttransmission medium 18 may otherwise be operatively coupled to the lightdiffusing element 30 using various optical connections includingsplices, butt couplings and other light transmission couplings.

In the embodiment shown in FIG. 2, the surface 12, such as the worksurface of an operating table 15, is shown located within a clean room14, whereas the electrically powered light source 16 is located outsideof the clean room 14. The low scatter light transmission medium 18advantageously allows light generated by the light source 16 to betransmitted a substantial distance with low light signal loss into theclean room 14 to the light diffusing element 30 where the light isdiffused and transmitted to the surface 12 of table 15 for disinfectingthe surface 12. As such, the light diffusing element 30 may be employedas a flexible remote light illuminator that allows continuoussterilization in wet, explosive, or other sterile environments, whilepositioning the light source 16 outside of the clean room 14. As such,the light source 16 does not need to be sterilized and may beelectrically powered from outside the clean room 14.

The low scatter light transmission medium 18 may include a transmissionfiber that may be a single fiber, a bundled (or ribbonized) collectionof fibers, a plastic optical fiber (POF), or other light transmissionmedium. The low scatter light transmission medium 18 may employ a fusedsilica rod, according to another embodiment, that can also be used asefficient delivery of light from the light source 16 to the lightdiffusing element 30. The low scatter transmission medium 18 may beconnected to the light diffusing element 30 by the optical coupler 20 orby butt coupling to the light diffusing element 30.

The light diffusing element 30 may be configured as a single lightdiffusing fiber or may be bundled (or ribbonized) collections of lightdiffusing fibers. The light diffusing fiber 30 may be flexible, thusallowing ease in installation within the channel 24. In one embodiment,the light diffusing fiber 30 has a diameter of 1,000 microns or less,and more particularly of about 250 microns. In other embodiments, thelight diffusing fiber 30 may be more rigid such as in the form of alight diffusing rod having a diameter greater than 1,000 microns.

One embodiment of a light diffusing fiber 30 is illustrated having atypical cross-sectional structure shown in FIG. 1. The light diffusingfiber 30 may include the formation of random air lines or voids in oneof the core and cladding of a silica fiber. Examples of techniques fordesigning and forming such light diffusing fibers may be found, forexample, in U.S. Pa. Nos. 7,450,806; 7,930,904; and 7,505,660, and U.S.Patent Application Publication No. 2011/0305035, which are herebyincorporated by reference. The light diffusing fiber 30 has a glass core32 which may include an F-doped core. An SiO₂ cladding layer 34 havingair lines for scattering light is shown surrounding the core 32. Thecladding layer 34 may be formed to include air lines or voids to scatterthe light and direct the light through the side walls. It should beappreciated that the random air lines 34 may be disposed in the core 32or in the cladding 36 or in both, according to various embodiments. Itshould be appreciated that high scattering losses are generallypreferred in the light diffusing fiber 30. A low index polymer primaryprotective layer 36 generally surrounds the cladding layer 34.Additionally, an outer secondary layer 38 may be disposed on the primaryprotective layer 36. Primary protective layer 36 may be soft andliquidy, while secondary layer 38 may be harder.

The secondary layer 38 may include a photoreactive agent according toone embodiment. The photoreactive agent may be provided as the secondarycoating having a hardness greater than the first cladding coating. Thephotoreactive agent may include materials such as TiO₂, W₂O₃, and othercatalytic elements that photo-oxidizes when the light activates thematerial.

Scattering loss of the light diffusing fiber 30 may be controlledthroughout steps of fiber manufacture and processing. During the airline formation process, the formation of a greater number of bubbleswill generally create a larger amount of light scatter, and during thedraw process the scattering can be controlled by using high or lowtension to create higher or lower loss, respectively. To maximize lossof light, a polymeric cladding may be desirably removed as well, over atleast a portion of the light diffusing fiber 30 length if not all.Uniform angular loss in both the direction of light propagation, as wellas in the reverse direction can be made to occur by coating the lightdiffusing fiber 30 with inks that contain scattering pigments ormolecules, such as TiO₂. An ultraviolet light source may be used aswell, with a fluorescent dye or phosphor materials applied to the fibercladding (effectively down converting the ultraviolet wavelength oflight with approximately 100 percent efficiency to a desiredwavelength). Use of such fluorescence down-conversion creates veryuniform angular light distribution. The high scattering light diffusingfiber 30 may have a modified cladding to promote scattering anduniformity. Intentionally introduced surface defects on the lightdiffusing fiber 30 or core or cladding may also be added to increaselight output, if desired.

The light diffusing fiber 30 may have a region or area with a largenumber (greater than 50) of gas filled voids or other nano-sizedstructures, e.g., more than 50, more than 100, or more than 200 voids inthe cross section of the fiber. The gas filled voids may contain, forexample, SO₂, Kr, Ar, CO₂, N₂, O₂ or mixture thereof. Thecross-sectional size (e.g., diameter) of the nano-size structures (e.g.,voids) may vary from 10 nanometers to 1 micrometer (for example, 15nanometers to 500 nanometers), and the length may vary depending on thearea of the surface to be disinfected.

While the light diffusing fiber 30 is shown and described herein havingair lines, it should be appreciated that other light scattering featuresmay be employed. For example, high index materials such as GeO₂, TiO₂,ZrO₂, ZnO, and others may be employed to provide high scatter lighttransmission. It should further be appreciated the light diffusingelement 30 may be a light diffusing rod that is less flexible, has alarger diameter and may have no coating.

Referring to FIGS. 5-7, a light delivery system 10, according to anotherembodiment is illustrated employing a light diffusing element 30extending within the surface 12 and around the periphery of a table 15having a surface 12 to be disinfected. The light diffusing element 30may be a light diffusing fiber or light diffusing rod and is shownextending along all four side edges of a light transmissive medium 40,such as a glass panel. As such, the light diffusing element 30 edgelights the glass panel so that light passing through the light diffusingelement 30 is effectively illuminated into the glass medium. The glassmedium 40 may be made of a translucent material so that the lightfurther diffuses and illuminates the top surface. Additionally, thebottom surface of the glass medium 40 has a reflective surface 42 forreflecting light upward towards surface 12 to be disinfected.Additionally, edge coverings 44 are disposed along the peripheral edgesof the table outside of the light diffusing element 30 and may includean internal reflective surface 46 to reflect light back into the glassmedium 40. As such, light passing through the light diffusing element 30is reflected upwards by the bottom surface and inwards by the edgecoverings 44 into the glass medium 40 from where it propagates up tosurface 12 to be disinfected.

A method of disinfecting a surface by promoting a photochemical reactionwith the use of the light delivery system 10 will now be described. Themethod includes the step of coupling a light diffusing element 30 to asurface 12 to be disinfected. The surface 12 may be a table 15, such asan operating table used within a clean room. The method also includesthe step of supplying light having a wavelength to promote aphotochemical reaction to the light diffusing element 30. The methodfurther includes the step of applying the light output from the lightdiffusing element 30 to the surface 12 to promote a photochemicalreaction to disinfect the surface 12.

The method may further include the step of supplying the light from alight source 16 to a low scatter light transmission medium 18, andfurther coupling the low scatter light transmission medium 18 to thelight diffusing element 30. The light diffusing element 30 may bedisposed within a channel 24 formed in the surface 12. The surface 12may be disposed within a clean room 14 and the light source 16 may bedisposed outside of the clean room 14. The light diffusing element 30may be a light diffusing fiber having a glass core, a cladding, and aplurality of air lines disposed in one of the core and the cladding. Thecladding may include a coating comprising a photoreactive agent.

Accordingly, the light delivery system 10 and method advantageouslydelivers light from a light source 16 to a light diffusing element 30embedded within a surface 12 such as a table 15 to disinfect the surface12 with light generated by the light source 16. As such, the surface 12may be disinfected with light that is generated remotely and transmittedto the surface by way of the light diffusing element 30 in a manner thatis safe, easy to use and clean.

Various modifications and alterations may be made to the examples withinthe scope of the claims, and aspects of the different examples may becombined in different ways to achieve further examples. Accordingly, thetrue scope of the claims is to be understood from the entirety of thepresent disclosure in view of, but not limited to, the embodimentsdescribed herein.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thespirit or scope of the claims.

What is claimed is:
 1. A light delivery system to promote aphotochemical reaction for disinfecting a surface, the systemcomprising: a light source; and a light diffusing element operativelycoupled to the light source and further embedded within a surface to bedisinfected, wherein the light diffusing element outputs light to thesurface to promote a photochemical reaction to disinfect the surface. 2.The light delivery system of claim 1, wherein the light diffusingelement is disposed within a channel formed in the surface.
 3. The lightdelivery system of claim 1, wherein the light diffusing element iswithin the surface and about a periphery of a translucent material. 4.The light delivery system of claim 1 further comprising a low scatterlight transmission medium coupled between the light source and the lightdiffusing element.
 5. The light delivery system of claim 4 furthercomprising an optical coupler coupling the low scatter lighttransmission medium to the light diffusing element.
 6. The lightdelivery system of claim 1, wherein the surface is disposed within aclean room and the light source is disposed outside of the clean room.7. The light delivery system of claim 1, wherein the light diffusingelement comprises a light diffusing fiber.
 8. The light delivery systemof claim 7, wherein the light diffusing fiber comprises a glass core, acladding, and a plurality of air lines disposed in at least one of thecore and the cladding.
 9. The light delivery system of claim 8 furthercomprising at least one coating disposed on the cladding, the at leastone coating comprising a photoreactive agent.
 10. The light deliverysystem of claim 1, wherein the light diffusing element comprises a lightdiffusing rod.
 11. The light delivery system of claim 1, wherein thesurface is on a surgery table.
 12. The light delivery system of claim 1,wherein the light source generates light having at least one wavelengthin the range between 200 nm and 2,000 nm.
 13. The light delivery systemof claim 1, wherein the light source generates ultraviolet light.
 14. Amethod of disinfecting a surface by promoting a photochemical reaction,the method comprising: coupling a light diffusing element to a surfaceto be disinfected; supplying light having a wavelength to promote aphotochemical reaction to the light diffusing element; and applying thelight output from the light diffusing element to the surface to promotea photochemical reaction to disinfect the surface.
 15. The method ofclaim 14 further comprising: supplying the light from a light source toa low scatter light transmission medium; and coupling the low scatterlight transmission medium to the light diffusing element.
 16. The methodof claim 14, wherein the light diffusing element is disposed within achannel formed in the surface.
 17. The method of claim 14, wherein thesurface is disposed within a clean room and the light source is disposedoutside of the clean room.
 18. The method of claim 14, wherein the lightdiffusing element comprises a light diffusing fiber.
 19. The method ofclaim 18, wherein the light diffusing fiber comprises a glass core, acladding, and a plurality of air lines disposed in at least one of thecore and cladding.
 20. The method of claim 19, wherein the claddingcomprises a coating comprising a photoreactive agent.